I. Manufacturing Process
This bearing bracket is a dual-hole vertical support structure specifically designed for 3C products. It needs to meet the miniaturization, high precision, and lightweight requirements of 3C products. The core process utilizes a forged blank + CNC precision machining + surface treatment solution. The specific process is as follows:
1. Raw Material Selection: 6061-T6 aluminum alloy is selected (high structural strength, good machinability, suitable for the light load and high precision requirements of 3C products). For small-batch trial production, 6063 aluminum alloy (better surface treatment effect) can be used. Forged aluminum blanks are used (reducing internal porosity and improving structural density).
2. Blank Pretreatment: The forged aluminum blank undergoes solution treatment and aging to eliminate internal stress. Straightening ensures the flatness of the blank. After sawing to obtain the fixed-length blank, sandblasting is performed to roughen it and improve the clamping stability for subsequent processing.
3. CNC Precision Machining:
◦ Using a four-axis CNC machining center, the outer contours of the base and vertical support are first milled, then the bearing mounting holes are machined by boring (dual-hole machining is completed in one clamping, ensuring coaxiality);
◦ Drilling and tapping of mounting holes, milling of positioning grooves, chamfering and deburring are completed, and the bearing mating surfaces are precision bored and polished;
◦ For mass production, pneumatic tooling fixtures are used to improve clamping efficiency and machining consistency.
4. Surface Treatment:
◦ Black Hard Anodizing: The oxide layer thickness is controlled at 8~15μm, with a hardness ≥HV350, improving surface wear resistance and corrosion resistance (resisting wear and sweat corrosion during the assembly and use of 3C products), while matching the appearance design of 3C products.
◦ Passivation Treatment: Passivation is applied to non-exterior surfaces for rust prevention, avoiding oxidation of machined surfaces from affecting assembly accuracy.
◦ Conductive Anodizing: If the bracket needs to participate in electromagnetic shielding, a conductive anodizing process is used to ensure the conductivity continuity of the metal surface.
5. Inspection and Trial Assembly: Dimensional accuracy is checked using a 2D measuring instrument. Assembly and trial fitting are performed with the bearings and shafts of 3C products to verify smooth rotation and positioning accuracy, ensuring no jamming or abnormal noise.
II. Machining Accuracy
This bracket needs to meet the precision transmission requirements of 3C products. Core accuracy indicators align with the miniaturization technical requirements of the 3C industry, specifically as follows:
1. Dimensional Accuracy:
◦ Bearing mounting hole inner diameter tolerance: H7 grade (+0.018/0mm), suitable for the interference/transition fit requirements of miniature bearings in 3C products.
◦ Double bearing hole coaxiality: ≤0.01mm, ensuring smooth shaft rotation.
◦ Mounting hole position accuracy: ≤0.03mm, hole diameter tolerance H6 grade, ensuring precise assembly with the 3C product housing.
◦ Overall bracket dimensional tolerance: ±0.05mm, suitable for the compact internal installation space of 3C products.
2. Geometric Tolerances:
◦ Bearing mating surface flatness: ≤0.02mm/50mm, reducing bearing installation clearance errors.
◦ Perpendicularity of the vertical support sidewall to the base: ≤0.02mm, ensuring the vertical accuracy of bearing installation.
◦ Parallelism of the double support surfaces: ≤0.03mm, preventing runout during shaft rotation.
3. Surface Finish:
◦ Bearing mating surface roughness Ra0.4~0.8μm, reducing friction between the bearing and the bracket.
◦ Appearance surface (after anodizing) roughness Ra1.6μm, ensuring the aesthetic quality of 3C products.
◦ Non-mating surface roughness Ra3.2μm, meeting basic processing and usage requirements.
III. Industry Applications
These 3C product bearing brackets, due to their miniaturization, high precision, and lightweight characteristics, are widely used in the transmission and support structures of various 3C products. Core applications include:
1. Consumer Electronics Terminals:
◦ Smartphones/Tablets: Rotary bearing brackets for camera modules (e.g., the camera lifting/rotating mechanism of foldable phones), transmission bearing supports for side fingerprint recognition modules.
◦ Laptops: Bearing brackets for screen hinges (hing support structure of thin and light laptops), support bases for touchpad scroll axes.
◦ Wearable Devices: Rotary bearing brackets for smartwatch crowns, transmission supports for folding buckles of smart bracelets.
2. 3C Accessories:
◦ Wireless Chargers: Bearing supports for rotating charging bases, enabling charging angle adjustment.
◦ Gaming Peripherals: Keycap switch supports for mechanical keyboards (transmission bearing seats for high-end custom keyboards), rotary bearing brackets for joysticks in game controllers.
◦ Audio Equipment: Folding rotary bearing brackets for headphones, rotating speaker unit supports for Bluetooth speakers.
3. 3C Production Equipment:
◦ Miniature transmission bearing brackets for 3C product assembly lines (such as roller supports for mobile phone screen protector application machines) and precision shaft support seats for chip testing equipment, adapting to the high-precision transmission requirements of the production process.
